The present invention relates to a saw capture device. In particular, the present invention relates to a saw capture device couplable to a cutting block in order to guide a surgical cutting tool to resect a bone.
During orthopaedic surgery it is commonly necessary to resect a portion of a bone, in particular an end of the bone. For instance, during a total knee replacement procedure, it is necessary to resect the ends of the tibia and femur about the knee joint. There are similar requirements for resecting other bones for instance at a hip or a shoulder joint for the implantation of other prosthetic devices. In order to perform the resection, a cutting instrument, for instance an oscillating saw blade, is guided by a surgeon along a predetermined resection plane.
When performing a resection of a bone it is important to ensure that the resection occurs accurately along the predetermined resection plane in order to ensure that the implanted prosthesis is not misaligned. It is known to provide a cutting block, which is couplable to the bone, providing a permanent slot through which the surgeon passes the blade of the cutting instrument. The slot is aligned with the predetermined resection plane and the cutting block coupled to the bone, for instance by temporarily fixing to the bone with pins.
Alternative cutting blocks include a saw capture device that is attached to the cutting block. A side of the cutting block comprises a first guide surface and a side of the saw capture device facing the cutting block comprises a second spaced apart guide surface. The blade of the cutting instrument is captured between the side of the cutting block and the saw capture device. It is known for the saw capture device to be removable from the cutting block, for instance using pegs or pins. Removable saw capture devices are disclosed in U.S. Pat. No. 5,693,056 and U.S. Pat. No. 5,611,802. The saw capture device of U.S. Pat. No. 5,611,802 comprises interchangeable arms of different sizes arranged to wrap around bones of different diameters, which further improves the alignment of the cutting instrument, and so the accuracy of the resection. Advantageously, providing a removable saw capture device allows the saw capture device to be removed for cleaning the cutting block.
It can be necessary to perform resections of bones having different shapes and diameters. Furthermore, the resection may be performed using different surgical approaches, for instance anterior-posterior cuts, distal femoral cuts and proximal tibial cuts. Each type of resection typically requires a different form of cutting block, both to allow the block to couple effectively to the bone and also to allow the profile of the cutting block to closely conform to the bone. Providing a dedicated saw capture device for each form of cutting block requires a large number of separate surgical instruments to perform resections of a full range of bones.
It is an object of embodiments of the present invention to obviate or mitigate one or more of the problems associated with the prior art, whether identified herein or elsewhere.